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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous results demonstrate that hypoxia (low oxygen) diminishes calcium uptake by synaptosomes. The present studies examined the effects of low oxygen on calcium homeostasis in the digitonin-resistant (mitochondrial) and the digitonin-labile (nonmitochondrial) compartments of intact synaptosomes and their relation to altered membrane potentials. A 10-min hypoxic incubation in low-potassium media reduced total (-38.3%), mitochondrial (-43.3%), and nonmitochondrial (-27.8%) calcium uptake. In high-potassium media, low oxygen reduced mitochondrial (-41.2%) and total (-34.4%) uptake whereas nonmitochondrial (+ 6%) calcium uptake was essentially unaffected. A temporal analysis of nonmitochondrial calcium uptake revealed an initial depression (0-5 min) followed by a stimulation (5-10 min). Hypoxic-induced alterations in the subsynaptosomal distribution of calcium resembled those produced by uncouplers [FCCP (carbonylcyanide-p-trifluoromethoxyphenylhydrazone) or rotenone plus oligomycin]. 3,4-Diaminopyridine partially ameliorated the hypoxic- and FCCP-induced decreases in synaptosomal calcium uptake. Low oxygen reduced the total synaptosomal membrane potential (i.e., plasma plus mitochondrial membrane potential) as measured by an increased efflux of tetraphenylphosphonium ion. This hypoxic-induced efflux of tetraphenylphosphonium was slowed by pretreatment with 3,4-diaminopyridine. Thus, both drug and membrane potential studies suggest that hypoxic-induced alterations in the subcellular distribution of calcium may be due to an uncoupling mechanism and a collapse of the synaptosomal mitochondrial membrane potential.
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PMID:Subsynaptosomal calcium distribution during hypoxia and 3,4-diaminopyridine treatment. 405 92

The pathophysiological basis of pulmonary atelectasis is reviewed and risk factors that enhance lung collapse are discussed. Management strategies to reduce or eliminate risk factors and to prevent collapse are discussed and the rational bases of these strategies are identified. Instability of lung alveoli is a consequence of surface tension and regional differences in alveolar size. The inherent tendency of alveoli to collapse is enhanced by the following risk factors; low lung volume, high closing volume, oxygen therapy, a rapid shallow ventilatory pattern, chronic lung disease, smoking, obesity, postoperative pain following abdominal or thoracic surgery, narcotic induced ventilatory depression, and neurological, neuromuscular, muscular and musculoskeletal diseases associated with mechanical impairment of respiratory function. The primary goal of perioperative respiratory management is prevention of atelectasis. Appropriate management strategies include physiotherapy and delay of elective surgery if substantial improvement in respiratory status can be achieved by specific treatments such as antibiotics, bronchodilators, steroids, and reduction of tobacco use and caloric intake. In selected cases, elective postoperative controlled ventilation may be indicated.
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PMID:Pulmonary atelectasis after anaesthesia: pathophysiology and management. 611 89

1. The dependence of membrane potential (delta psi) on the rate of respiration in darkened intact cell suspensions of Rhodopseudomonas capsulata was distinctly non-linear: severe inhibition of respiration with either rotenone or KCN led to only a small drop in delta psi. 2. In the presence of 0.3 microMs carbonylcyanide p-trifluoromethoxyphenylhydrazone [CF3OPhzC(CN)2] the dependence of delta psi on respiratory rate became linear. Consequently, and particularly at lower concentrations of CF3OPhzC(CN)2, there was a pronounced, synergistic depression of the respiratory delta psi with CF3OPhzC(CN)2 and either rotenone or KCN. 3. Antimycin A, at a concentration which strongly inhibited the photosynthetic electron transport chain, only slightly lowered the light-induced delta psi in anaerobic cell suspensions. Antimycin and CF3OPhzC(CN)2 synergistically lowered delta psi generated by illumination. 4. The light-induced delta psi in anaerobic cells was only about 1.5-times larger than the respiratory-induced delta psi in darkened cells. Nevertheless it required approximately 16-times more CF3OPhzC(CN)2 to collapse the photosynthetic delta psi than the respiratory delta psi. 5. These results are discussed with reference to the ionic current/delta psi relation described in [J.B. Jackson (1982) FEBS Lett. 139, 139-143]. The unifying feature is that the intrinsic conductance of the cell membrane is strongly dependent on delta psi but the conductance due to CF3OPhzC(CN)2 is independent of delta psi.
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PMID:The influence of the ionic conductance on the relation between electron transport and proton-motive force in intact cells of Rhodopseudomonas capsulata. 629 8

In 200 young patients with apparently idiopathic spontaneous pneumothorax, the following radiologic features were analyzed: degree of collapse on the initial chest film, areas of atelectasis, and presence of blebs, apical opacities, fibrous adhesions, pleural effusions, and controlateral shift of mediastinal structures. Confrontation of apical changes with pathologic findings in operative specimens suggests that mesothelial rupture with reactive hyperplasia results in a "pneumatization chamber" visible as a bullous image. Following drainage, homolateral shifts of mediastinum and four cases of pulmonary edema were recorded. Risk factors for pulmonary edema include severe pulmonary collapse with areas of atelectasis, persisting for more than 48 hours and an aspiration which either exceeded 1.5 l. of air or was performed with a depression of more than 30 cm of water.
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PMID:[Radiology of spontaneous pneumothorax in young patients. Apropos of 200 cases]. 632 55

Dextropropoxyphene is a widely prescribed synthetic opiate-like drug of uncertain analgesic efficacy which, in acute overdosage, manifests all the features of opiate toxicity. It is rapidly absorbed and, in association with other central nervous system depressants such as alcohol or benzodiazepine drugs, may be rapidly fatal. Seriously overdosed patients are comatose with respiratory depression, vomiting, seizures and circulatory collapse; small pupils are a useful diagnostic marker. The first priority is to establish the airway and treat convulsions, if present. All the features of overdosage are then rapidly and safely reversed by the specific opiate antagonist naloxone given intravenously. High tissue concentrations and slow elimination of dextropropoxyphene metabolites make continued and intensive monitoring after resuscitation essential because sudden unpredictable deterioration may occur for up to 24 hours. Other more slowly toxic co-ingestants such as paracetamol (acetaminophen) are often present and should be detected and treated as necessary. Dextropropoxyphene poisoning is now probably one of the most common causes of self-poisoning death because, although there is an effective antidote, subjects frequently succumb before treatment can be made available.
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PMID:Dextropropoxyphene overdosage. Pharmacological considerations and clinical management. 634 64

That a decline in oxygen consumption (VO2) might herald onset of septic shock prior to hemodynamic collapse is suggested by previous observations in humans and animals in which VO2 appeared to be suppressed in systemic sepsis, despite normal or supranormal cardiac output, and in cellular and mitochondrial preparations exposed to endotoxin, despite adequate flow of perfusate. That a supranormal VO2 might be one of the best predictors of ultimate survival is suggested by data collected from humans during various stages of septic shock. To evaluate VO2 as an early indicator of sepsis, the effect of endotoxemia was observed in 20 rhesus monkeys divided into groups according to hypodynamic, normodynamic, and hyperdynamic blood flow states; the effect of sepsis was observed in seven preterminal septic humans during the final hours of their lives. VO2 was measured using a new device that evaluates expired gases by means of a relatively simple feedback-controlled gas replenishment technique. In neither the primates nor the humans was it possible to demonstrate a flow-independent depression of VO2. VO2 was distinctly elevated in each of the humans over some interval during the final day of life. These observations, plus an in-depth review of the literature, suggest that other variables, particularly peripheral vascular resistance, systemic and regional blood flow, and oxygen extraction fraction attempt to accommodate in an effort to sustain VO2. Probability of survival in sepsis appears to be enhanced by VO2 and cardiac output that are supranormal; yet even when VO2 is elevated, death can ensue within minutes to hours. Significant decline in VO2 is a grave prognostic sign, almost always preceded by a relatively easily detected hemodynamic change. Systemic VO2 appears to represent neither a specific early indicator of sepsis nor a certain prognosticator of survival outcome; it might provide useful information regarding adequacy of resuscitation.
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PMID:Oxygen consumption in septic shock: collective review. 638 53

A prospective study of the development of necrosis of the femoral head was performed in 34 patients with fractures of the femoral neck. Technetium-99m MDP images of the hip regions were obtained immediately after nailing of the hip and at four, eight and 12 months. There was a good correlation between qualitative and numeric evaluation of isotope uptake in the femoral heads. Comparison of the activity level in the femoral head on the fracture side with that in the contralateral control site showed activity ratios to vary between < 1.0 for those heads showing a general reduction in activity on conventional images to > 1.4 with a mean of 2.0 for those showing increased activity. The initial postoperative images in 2/7 undislocated fractures showed a marked depression in femoral head activity on the fracture side; 13/21 dislocated fractures showed a similar defect suggesting a significant loss of bone remodeling. Normal Tc-99m activity in the femoral head (category 2) was observed in two fracture cases imaged within 24 hours of fracture, just prior to nailing. Repeat studies within one week of fracture and nailing demonstrated a marked depression in activity (category 0). Radiographic evidence of collapse later developed in both patients. The perfusion and blood pool images were useful for identifying femoral heads with deficient circulation. This investigation has demonstrated that the nailing procedure may threaten the vascular condition of the femoral head in hip fracture, that a dead head may be radiographically normal and clinically asymptomatic, and that the metabolic condition of the femoral head may be expressed in numeric terms suitable for statistical analysis.
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PMID:Dynamics of Technetium-99m methylenediphosphonate imaging of the femoral head after hip fracture. 644 42

Intravenous injection of oxytetracycline HC1 (OTC) in propylene glycol (PG), OTC in saline solution, and PG alone in sheep had no significant (P less than 0.01) effects on total plasma calcium concentrations over a 60-minute period. In contrast, ionized calcium concentrations in whole blood were significantly (P less than 0.01) depressed for approximately 3 minutes after OTC in PG and OTC in saline solution, IV. A slight depression of ionized calcium concentrations was noticed after injection of PG alone. Seemingly, calcium chelation by OTC may be a major factor in the collapse syndrome of ungulates given preparations containing OTC by rapid IV injection.
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PMID:Effects of oxytetracycline in propylene glycol, oxytetracycline in saline solution, and propylene glycol alone on blood ionized calcium and plasma total calcium in sheep. 647 80

Healing of the external defects by the primary tension, under the scab, or by the secondary tension through the suppuration as well as the formation of granulation tissue (GT) in other organs, represent an adequate homeostatic response to the injury with stereotype kinetics of the inflammation and regeneration. The altered general and local responsiveness trophic disorders, burn and radiation trauma result in collapse of the autoregulatory mechanisms, pronounced disturbance of phagocytosis, microcirculation, mediator and contact cell interaction. This provokes the inhibition of fibroblast proliferation, depression and perversion of fibrillogenesis and the granulation tissue maturation, the formation of abnormal granulation tissue with repeated wakes of sclerosis, necrosis and inflammation, formation of persisting wounds, ulcers, hypergranulations or chronic inflammatory processes. Homeostatic protective response transforms into the pathologic response due to dissociation between the inflammation and regeneration and formation of "vicious circle".
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PMID:[Granulation tissue: inflammation and regeneration]. 671 9

There have been many studies of the development of an industrial work force with all its attendant hardships as newly proletarianized peasants were thrown off the land and into factory labor. The author postulates that a similar process occurred in the creation of at least one modern "profession"--nursing--as the traditional autonomy of private practive nursing was displaced by institutional nursing in hospitals and nursing homes. Prior to the Depression, most nurses worked in private duty--as independent entrepreneurs--without the regimentation, rigid division of labor, and intense supervision characteristic of modern hospitals. The collapse of the U.S. economy made it impossible for most nurses to continue to earn a living privately at the same time that hospitals required cheap labor power in order to develop as viable businesses. Despite the promise of job security in hospital work, most nurses resisted the change by criticism, sabotage, walking away from job, and attempts at unionization. Hospitals sought in response to inculcate loyalty by a variety of methods, including screening of applicants, in-service training, and professional ideology. In some instances, hospitals coerced private nurses into "staff" jobs by threatening their ability to secure business on their own. By the end of World War II, the majority of nurses were employed, for the first time, as wage earners for institutions. The entire period was marked by such discord and revolt on the part of nurses, however, that the American Nurses' Association was transformed as an organization in order to avoid massive unionization. The study points out that this unwritten history of nursing has been obscured by professional nursing leaders who are still suppressing revolts of rank-and-file nurses against the conditions of hospital work.
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PMID:The proletarianization of nursing in the United States, 1932--1946. 698 72


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